Eggs on various athletes at the outset (3)
I believe the answer is:
'eggs' is the definition.
(term for egg cells)
'on various athletes at the outset' is the wordplay.
'at the outset' suggests taking the first letters (the outset is the beginning).
The first letters of 'on various athletes' is 'OVA'.
(Other definitions for ova that I've seen before include "Prerequisite for procreation" , "Female egg cells" , "Likely end for Russian Fed cup players" , "Female reproductive cells" , "Multiple Latin eggs" .)